End products of purine degradation very from species to species. The end product of purine degradation is urate in humans, hominoid primates and new world monkeys, allantoin by uricase in mammals other than primates and old world monkeys, allantoate by allantoinase in some teleosts, urea by allantoicase in fish and amphibians and ammonia by urease in many invertebrates.The degradation of purines to urate is common to all animal species, while the degradation of urate is much less complete in higher animals. We have reported that in marine fish, the degrading enzymes of purines to urate are located in the cytosol, while the degrading enzymes of urate to urea are located in the peroxisomes. This shows that in purine degradation, peroxisomal enzymes have been lost during evolution. Allantoinas (ALN) and allantoicase (ALC) are different protein in fish liver, whereas the two enzymes form a complex in amphibian liver.We examined how the mechanism to form amphibian allantoinase-allantoicase
… Morecomplex (ALNC) is lost in higher animals during animal evolution.(1) The cDNA encoding allantoinase of the subunit of amphibian ALNC was sequenced. We got some clones from λat 11 library using anti allantoinase of bullfrog. (2) In saltwater fish liver, the end products of purine degradation were urea and glyoxylate. Glyoxylate may be converted to glycine by alanine : glyoxylate aminotransferase for the reutilization of purine carbons. (3) It is generally accepted that all of the allantoin-degrading enzymes were lost during mammalian evolution. Suprisingly, ureidoglycollate lyase has been found in a mammalian tissue. The apparent Km (17 mM) of the rat enzyme for ureidoglycollate was much higher than that (0.33 mM) of fish-liver ureidoglycollate lyase. Mammals have lost the function in vivo by elevating the Km for ureidoglycollate during evolution. (4) We found free ALN only with ALN activity which is differ from ALN subunit composed of ALNC. The enzyme shows the middle type of fish ALN and amphibian ALNC. (5) ALN and ALC were purified from the each liver of sardine (salt water), mullet (brackish water) and crucian carp (fresh water). Amino acid sequences were determined from the part of purified ALN and ALC by protein sequencer. The cDNA of each fish was synthesied with RT-PCR using mRNA and determined full-length by DNA sequencer. In defferent habitat, DNA sequence of each fish ALN and ALC signal of transference to and destribution in peroxisomes. We compared with subunit of fish ALN and amphibian ALNC.3.ラット肝に哺乳類には存在しないと思われていたUreidoglycollate lyaseが存在すること、Kmの濃度を高める事によって,動物が高等なほど酵素活性を失っていく。4.両生類の牛ガエルの肝臓にALNCとは異なるALN活性のみを示すfreeのALNが存在することを明らかにした。本酵素は酵素学的、免疫学的性質から魚類ALNと両性類ALNCの中間型であることが示唆された。5.海棲のイワシ、汽水域のボラ、淡水のフナの肝臓よりALN及びALCを精製し、一部のアミノ酸配列より、プライマーを設計した。mRNAのRT-PCR反応により合成したcDNAを用いて、full-lengthを決定した。生息環境の異なる、各種魚類のALN,ALCの配列により,ペルオキシソームへの移行シグナル及び局在化シグナルを解析し、複合体ALNCを構成する両性類の酵素のサブユニットALNと比較した。 Less